1. Field of the Invention
The invention relates to a manufacturing method of an image forming apparatus, a manufacturing apparatus of an image forming apparatus, and the image forming apparatus manufactured by the manufacturing method.
2. Related Background Art
Hitherto, as electron emitting devices, mainly, two kinds of devices, i.e., a device using a thermionic emitting device and a device using a cold cathode electron emitting device have been known. As cold cathode electron emitting devices, there are a field emission type (hereinafter, abbreviated as an FE type), a metal/insulating layer/metal type (hereinafter, abbreviated as an MIM type), a surface conducting type electron emitting device, and the like.
As an example of the FE type, there has been known a device disclosed in W. P. Dyke and W. W. Dolan, xe2x80x9cField Emissionxe2x80x9d, Advances in Electron Physics, 8,89, 1956, C. A. Spindt, xe2x80x9cPhysical Properties of Thin-Film Field, Emission Cathodes with Molybdenum Conesxe2x80x9d, J. Appl. Phys., 47,5248, 1976, or the like.
As an example of the MIM type, there has been known a device disclosed in C. A. Mead, xe2x80x9cOperation of Tunnel-Emission Devicesxe2x80x9d, J. Appl. Phys., 32,646, 1961, or the like.
As an example of the surface conducting type electron emitting device, there has been known a device disclosed in M. I. Elinson, Radio Eng. Electron Phys., 10,1290, 1965, or the like.
The surface conducting type electron emitting device uses a phenomenon in which an electron emission occurs by the supplying of current to a thin film of small area formed on a substrate so as to be in parallel with the film surface. As a surface conducting type electron emitting device, there has been reported a device using a SnO2 thin film by Elinson et al., mentioned above, a device using an Au thin film [G. Dittmer, xe2x80x9cThin Solid Filmsxe2x80x9d, 9,317, 1972], a device using an In2O3/SnO2 thin film [M. Hartwell and C. G. Fonstad, IEEE Trans. ED Conf., 519, 1975], a device using a carbon thin film [Hisashi Araki, et al., Vacuum, Vol. 26, No. 1, pages 22, 1983], or the like.
As a typical device construction of those surface conducting type electron emitting devices, a device construction of M. Hartwell mentioned above is diagrammatically shown in FIGS. 7A and 7B.
In FIGS. 7A and 7B, reference numeral 71 denotes a substrate; 72 and 73 element electrodes; and 74 a conductive film made of a metal oxide thin film or the like formed in an H-shaped pattern by sputtering. An electron emitting portion 75 is formed by a current supplying process called a current supply forming, which will be explained hereinbelow. An interval L between the element electrodes in the diagram is set to 0.5 to 1 mm and Wxe2x80x2 is set to 0.1 mm.
Hitherto, in those surface conducting type electron emitting devices, generally, the electron emitting portion 75 is preliminarily formed by subjecting the conductive film 74 to the current supplying process called a current supply forming prior to performing an electron emission. That is, in the current supply forming, a DC voltage or a voltage of very moderately increased magnitude, for example, at a rate about 1 V/min, is applied across the conductive thin film 74 so that a current flows, thereby locally breaking, deforming, or degenerating the conductive thin film and forming the electron emitting portion 75 in an electrically high resistance state.
In the electron emitting portion 75, a crack occurs in a part of the conductive film 74, and an electron emission is performed from a portion near the crack. In the surface conducting type electron emitting device on which the current supply forming process has been performed, a voltage is applied to the conductive thin film 74 and a current is supplied to the device, thereby emitting electrons from the electron emitting portion 75.
In the surface conducting type electron emitting device, a method whereby carbon or/and its compound are formed in the electron emitting portion of the surface conducting type electron emitting device by a new manufacturing method called an activating step, thereby remarkably improving electron emitting characteristics, has been proposed (JP-A-7-235255).
According to the activating step, in the manufacturing method of the surface conducting type electron emitting device, a device in which a pair of electrodes and a conductive film are formed is put in a vacuum ambience and is subjected to a forming step, and thereafter, organic material gas having carbon is introduced into the vacuum ambience, and a pulse-like voltage which is properly selected is applied to the device for a few to several tens of minutes. According to this step, the characteristics of the electron emitting device, namely, an electron emission current Ie, remarkably increases and is improved while keeping unchanged a threshold value for the voltage.
However, in the image forming apparatus using the above conventional electron emitting device, there is a case where the following problems occur.
(1) In a large image forming apparatus, an electron source substrate (rear plate) on which a plurality of electron emitting devices are formed and a face plate on which a fluorescent body or the like is formed are positioned so as to keep desired relative positions, and are assembled and temporarily fixed at a predetermined distance of a few millimeters or less, and thereafter, the temperature is raised up to a temperature at which an adhering material such as frit glass or the like is softened, and a pressure is applied so that those plates are adhered, together with a space between them thereby forming a vacuum envelope (this step is called a heat seal bonding step). However, since the distance between the electron source substrate and the face plate is short and the conductance of the gas is small, in an exhausting step in the image forming apparatus subsequent to the seal bonding step, it takes time to exhaust the space to an adequate degree of vacuum through an exhaust pipe or, if the exhausting step is finished in a short time, the degree of vacuum in the apparatus is low, or a pressure fluctuation occurs. There is, consequently, a case where a degree of vacuum which is necessary for stable electron emitting characteristics cannot be obtained.
Although a high positioning precision is required in the relative arrangement between the electron emitting device and the fluorescent body in order to prevent a color deviation or the like, there is a case where the necessary positional precision cannot be obtained due to the positional deviation or the like due to a thermal expansion in the seal bonding step or the softening of frit glass that is used for seal bonding. As a device in which they are seal bonded in the vacuum, a method of using rod glass of a low melting point and adhering and introducing into a vacuum apparatus has been disclosed in JP-A-6-196094. Even in this case, however, postional deviation during the frit melting cannot be avoided.
Further, in a case where the electron emitting device which is used in the image forming apparatus is a surface conducting type electron emitting device, in the introduction of the gas into the vacuum envelope in association with the activating step of the surface conducting type electron emitting device, the gas is introduced through the exhaust pipe into the vacuum envelope in which the face plate and the rear plate are adhered while keeping the distance therebetween to a few millimeters or less. There are, consequently, problems in manufacturing such as that the conductance of the exhaust pipe and the vacuum envelope for the gas is small, it is difficult to obtain a constant pressure for a whole region in the vessel (vacuum envelope), it takes time until the pressure is stabilized, and the like.
(2) In the surface conducting type electron emitting device, after the activating step is performed, the gas used in the activating step and water, oxygen, CO, CO2, hydrogen, and the like are adsorbed to the electron source substrate or the material constructing the image forming apparatus, for example, the face plate having the fluorescent body. It is necessary to eliminate the adsorbed gas or the like in order to realize the stabilization of the electron emitting characteristics and to prevent a discharge by the remaining gas or the like. For this purpose, a step of exhausting through the exhaust pipe while baking the vacuum envelope after the seal bonding step, is needed.
According to the above step, however, since the conductance of the vessel and the exhaust pipe for the gas is small, the gas which is generated from the material cannot be always sufficiently exhausted and the stable electron emitting characteristics cannot be obtained, and there is a case of occurrence of a luminance fluctuation, decrease in life, and the like.
Further, a consistent manufacturing apparatus of the image forming apparatus which can solve the above problems and in which a re-contamination due to a re-adsorption of water, oxygen, hydrogen, CO, CO2, or the like to each of the degassed members does not occur, is demanded.
It is an object of the invention to provide an excellent manufacturing method and manufacturing apparatus of an image forming apparatus which can solve the foregoing problems, and to provide the image forming apparatus which is obtained by use of the manufacturing method and manufacturing apparatus.
To accomplish the above object, according to the invention, there is provided a method of manufacturing an image display apparatus, whereby a first substrate on which fluorescent body exciting means is arranged and a second substrate in which a fluorescent body which emits light by the fluorescent body exciting means is arranged are arranged so as to face each other and are adhered through joining members at their peripheries, wherein a seal bonding step of adhering the first and second substrates through the joining members and a step of position matching the first and second substrates are executed in a vacuum.
According to the invention, there is provided an apparatus for manufacturing an image display apparatus in which a first substrate on which fluorescent body exciting means is arranged and a second substrate in which a fluorescent body which emits light by the fluorescent body exciting means is arranged are adhered through joining members at their peripheries, comprising: a vacuum chamber; position adjusting means for moving the first substrate and/or the second substrate into the vacuum chamber in X, Y, and xcex8 directions; position adjusting means for moving the first substrate or the second substrate in a Z direction; heating means for heating the first and second substrates; and exhausting means for exhausting the inside of the vacuum chamber.
According to the invention, there are disclosed the image forming apparatus manufactured by the manufacturing method of the image forming apparatus of the invention and the image forming apparatus manufactured by the manufacturing apparatus of the image forming apparatus of the invention.
According to the invention, there is provided a manufacturing method of an image forming apparatus, whereby a step of seal bonding a plurality of members constructing a vacuum envelope including an electron source and an image forming member is executed in a vacuum ambience and the seal bonding step comprises: a step of heating and performing an evacuation while keeping the electron source and the image forming member at a desired distance; and a step of observing a relative positional relation of the electron source and the image forming member and adhering the plurality of members constructing the vacuum envelope while keeping a predetermined positional relation between the electron source and the image forming member at a temperature near a seal bonding temperature. According to this manufacturing method, since the vacuum envelope is formed by adhering the members while keeping the electron source and the image forming member in a predetermined positional relation at a temperature near the seal bonding temperature, the deviation of the relative position due to the thermal expansion, softening of frit glass, or the like can be corrected, and the power source substrate and the face plate can be adhered at a high positional precision.
The temperature is raised to the seal bonding temperature by separating the electron source substrate and the face plate at only an interval such that an enough conductance for the gas can be obtained and a degassing from the members is sufficiently executed and, after that, they are adhered, so that the vacuum vessel of a high vacuum degree can be formed and the stable electron emitting characteristics can be obtained. In a case of using the surface conducting type electron emitting device, by introducing the activating gas by separating the electron source substrate and the face plate at only an interval such that an enough conductance for the gas can be obtained, the activating gas can be easily introduced to the electron source substrate and the activation can be uniformly performed.
Further, the temperature is raised to the seal bonding temperature while keeping an interval between the electron source substrate and the face plate, and the seal bonding together with exhaustion, thereby performing this step together with the step of removing the activating gas or the like adhered to the member. Therefore, the vacuum degree which exerts an influence on the electron emitting characteristics can be improved and the heat processing step can be reduced.
That is, one of the inventions of the manufacturing method of the image forming apparatus according to the invention can be said as follows.
It is a manufacturing method of an image forming apparatus having a first substrate and a second substrate, in which the first and second substrates are arranged so as to face each other, a space that is airtight with respect to the outside is provided between the first and second substrates, and a fluorescent body and means for exciting the fluorescent body are provided in the airtight space, comprising:
a seal bonding step of adhering the first and second substrates through joining members; and position matching step of matching relative positions of the first and second substrates, wherein the seal bonding step and the position matching step are executed in a desired ambience different from the atmospheric ambience.
It is also a manufacturing method of an image forming apparatus having a first substrate and a second substrate, in which the first and second substrates are arranged so as to face each other, a space that is airtight for the outside is provided between the first and second substrates, and a fluorescent body and means for exciting the fluorescent body are provided in the airtight space, comprising:
a heating step of heating joining members in order to adhere the first substrate and the second substrate through the joining members; and a position matching step of matching relative positions of the first and second substrates in a state where the joining members are heated wherein, also, it is suitable that the heating and positioning steps are performed in a desired atmosphere.
According to the above inventions, the airtight space is formed by adhering the first and second substrates. A frame or a spacer can be also provided between the first and second substrates. The ambience upon adhering is reflected to the ambience of the airtight space. Therefore, it is sufficient to adjust the ambience upon adhering to an ambience such that the inside of the airtight space becomes a requested ambience. In this instance, by performing the adjustment of the ambience in a state where the interval between the first and second substrates is larger than the interval after they were adhered, the adjusted ambience can be more easily reflected to the ambience of the airtight space (portion which becomes the airtight space after adhering), so that the above method is preferable.
One of the inventions of the manufacturing apparatuses of the image forming apparatus regarding the invention can be also said as follows.
It is a manufacturing apparatus of an image forming apparatus having a first substrate and a second substrate, in which the first and second substrates are arranged so as to face each other, a space that is airtight for the outside is provided between the first and second substrates, and a fluorescent body and means for exciting the fluorescent body are provided in the airtight space, comprising:
a chamber which can set an inner ambience to a desired ambience; heating means for heating joining members in the chamber in order to adhere the first and second substrates through the joining members; and position matching means for matching relative positions of the first and second substrates in the chamber in a state where the joining members are heated.
The present invention also provides a method of manufacturing a panel device provided with first and second substrates arranged in opposition to each other and bonded together comprising steps of:
adjusting relative positions of the first and second substrates; and pressing to bond the first and second substrates with common means; and provides a method of manufacturing a panel provided with first and second substrates arranged in opposition to each other and bonded together comprising steps of:
moving relatively first holding means for holding the first substrate and second holding means for holding the second substrate, thereby adjusting positions thereof; and approaching the first and second holding means to each other, thereby pressing to bond the first and second substrates together.
According to the above manufacturing method, wherein the adjusting the position and the bonding are performed at a heating state, the positions can be adjusted in a high accuracy desirably. And, the position adjusting and the pressing may be performed in a desired atmosphere.
Further present invention provides an apparatus for manufacturing a panel device provided with first and second substrates arranged in opposition to each other and bonded together comprising:
adjusting means for adjusting relative positions of the first and second substrates, the adjusting means also operating to press the first and second substrates thereby bonding the substrates together.